I downloaded a set of "Victorian Grunge" textures from the website:
http://af-studios.deviantart.com/art/Victorian-grunge-texture-pack-125784217 and used Tip #4 (size one image to match another).
I resized the texture (number 1 of the set of 5) to match the original Santa image.
Texture layer is on top - blended with Lighten mode, Opacity = 61% and Fill = 96%, giving it a very subtle effect.
This resizing-to-fit is a cool technique that I was not aware of before Helen's class.